问题 问答题 简答题

简述预防井下电气火灾检查的注意事项。

答案

参考答案:

(1)电缆发生短路故障,高低压开关由于断流容量不足而不能断弧,引燃电缆。在检查中要检查高低压开关断流容量,校验高、低压开关设备及电缆的动稳定性及热稳定性,校验整定系统中的断电保护是否灵敏可靠。

(2)为了防止已着火的电缆脱离电源或火源后继续燃烧,必须采用合格的矿用阻燃橡套电缆。

(3)电缆不准盘圈成堆或压埋送电,检查电缆悬挂要符合《规程》要求。

(4)必须有断电保护,并按《规程》进行规定,保证灵敏可靠。若开关因短路跳闸,不查明原因不许反复强行送电。

(5)高压电缆接线盒是否符合规定,接线盒是否有可燃物。

(6)矿用变压器接线端子接触不良,或变压器检修时调入异物会造成高压短路。变压器不定期化验,会造成绝缘油失效,使变压器升温,发生过热造成套管炸裂,绝缘油喷出着火。

(7)井下不准用灯泡取暖,照明灯应悬挂,不准将照明灯放在易燃物上。

(8)架线电机车运行时产生电弧,当架空线离木棚太近或接触木棚时,高温电弧可能引燃木棚着火。另外,当架线段落在高压铠装电缆外皮上,直流电弧沿电缆燃烧,烧毁电缆的铠装和油倞纸绝缘。为防止上述事故发生,应严格按规定架设架线。架设电机车行使的巷道,必须是锚喷、彻渲或混凝土棚支护。

(9)检查变配电硐室是否备有足够的消防灭火器材,机电硐室不得用可燃性材料支护,并应有防火门。

阅读理解

About six years ago I was eating lunch in a restaurant in New York City when a woman and a young boy sat down at the next table,I couldn’t help overhearing parts of their conversation.At one point the woman asked,“So,how have you been?" And the boy -who could not have been more than seven or eight years old-replied.“Frankly, I've been feeling a little depressed lately."

This incident stuck in my mind because it confirmed my growing belief that children are changing.As far as I can remember, my friends and I didn’t find out we were “depressed”,that is,in low spirits,until we were in high school.

Undoubtedly a change in children has increased steadily in recent years.Children don't seem childlike anymore.Children speak more like adults,dress more like adults and behave more like adults than they used to.

Whether this is good or bad is difficult to say, but it certainly is different.Childhood as it once was no longer exists.Why?

Human development is depended not only on born biological states,but also on patterns of gaining social knowledge.Movement from one social role to another usually involves learning the secrets of the new social posifions.Children have always been taught adult secrets,but slowly and in stages;traditionally,we tell sixth graders things we keep hidden from fifth graders.

In the last 30 years,however, a secret-revelation(揭示)machine has been equipped in 98 percent of American homes.It is called television.Television passes information to all viewers allke,whether they are children or adults.Unable to resist the temptation(诱惑),many children turn their attention from printed texts to the less challenging,more attractive moving pictures.

Communication through print,as a matter of fact, allows for a great deal of control over the social information which children will gain.Children must read simple books before they can read complex materials.

小题1:According to the author, feeling depressed is      

A.a sure sign of a mental problem in a child

B.a mental state present in all humans, including children

C.something that cannot be avoided in children’s mental development

D.something hardly to be expected in a young child小题2:Traditionally, a child is supposed to learn about the adult world     

A.through connection with society

B.gradually and under guidance

C.naturally without being taught

D.through watching television小题3:According to the author’that today’s children seem adultlike results from   

A.the widespread influence of television

B.the poor arrangement of teaching content

C.the fast pace of human scientific development

D.the rising standard of living小题4:What does the anthor think of communication through print for children?

A.It enables children to gain more social information.

B.It develops children’s interest in reading and writing.

C.It helps chlldren to read and write well

D.It can control what children are to learn.小题5:What does the author think of the change in today’s children?

A.He feels their adultlike behavior is so funny.

B.He thinks the change worthy of note.

C.He considers it a rapid development.

D.He seems to be upset about it.

单项选择题